Twin MIG welding apparatus

Abstract

A dual-electrode arc welding apparatus includes a body assembly adapted to be coupled to a source of electric power and directing two wire electrodes through a nozzle assembly to an associated workpiece at a working end of the apparatus. The body assembly is provided at a distal end with an adapter which channels the electrodes respectively through passages of a tip assembly in electrical contact with the adapter and the body assembly for conducting electric power to the electrodes. The tip assembly is removable from the adapter without removing the nozzle assembly and, upon removal of the nozzle assembly, the adapter is removable from the body assembly. The tip assembly may include a single tip body with dual passages therethrough or two discrete tips separately mounted on the adapter by either threaded engagement therewith or by being slidably received in externally threaded nipples and secured by collet nuts. Similarly, the adapter may be collet-mounted or threadedly engaged with the body assembly. Devices both with and without provisions for shielding gas are disclosed and fluid-cooled nozzle assemblies and body assemblies are disclosed. In certain embodiments, the electrodes are powered from separate power sources respectively connected to electrically separated first and second body members of a body assembly. The nozzle assembly may be removably mounted directly on the body assembly or on a docking body which is, in turn, removably mounted on the body assembly.

What is claimed is:  
     
       1. An arc welding apparatus for delivering two wire electrodes to a workpiece comprising: 
       a body assembly adapted to be coupled to a source of electric power and directing the electrodes toward a working end of the apparatus,  
       a nozzle assembly removably coupled to the body assembly for channeling other utilities to the working end,  
       an adapter electrically and mechanically coupled to the body assembly for receiving the electrodes therefrom and maintaining the electrodes spaced from each other and being provided with two externally threaded collet nipples disposed at a distal end thereof, and  
       two tips respectively slidably received in the collet nipples in electrical connection therewith and defining two channels for respectively slidably receiving and electrically contacting the electrodes and guiding them to the associated workpiece, and  
       two collet nuts respectively threadedly engageable with the nipples for securing the tips in place whereby  
       the tips are removable from the apparatus without rotation of the tips and without removing the nozzle assembly or the adapter.  
     
     
       2. The apparatus of  claim 1 , wherein the body assembly includes a body defining passages for respectively receiving the electrodes and a socket at a distal end of the body communicating with the passages, the adapter defining channels for respectively receiving the electrodes and being slidably receivable in the socket with the channels respectively communicating with the passages, and threaded fastening means for removably securing the adapter in the socket without rotation of the adapter relative to the socket. 
     
     
       3. The apparatus of  claim 1 , wherein the body assembly includes a body defining passages for respectively receiving the electrodes and an internally threaded socket at a distal end of the body communicating with the passages, the adapter having channels therein for respectively receiving the electrodes and being threadedly engaged in the socket to a mounted position with the channels respectively communicating with the passages. 
     
     
       4. The apparatus of  claim 1 , wherein each of the tips is threadedly engaged in the adapter. 
     
     
       5. The apparatus of  claim 1 , wherein the nozzle assembly has cooling water circulation passages therein, and further comprising conduits in the body assembly for passing cooling water from a source to the nozzle assembly and from the nozzle assembly to a drain. 
     
     
       6. The apparatus of  claim 5 , wherein the body assembly includes normally-closed valves in the conduits, the nozzle assembly including actuators engageable with the valves when the nozzle assembly is mounted on the body assembly for opening the valves. 
     
     
       7. The apparatus of  claim 1 , wherein the body assembly includes cooling water circulation passages therein, and means for coupling the conduits to a supply of cooling fluid. 
     
     
       8. The apparatus of  claim 1 , wherein the body assembly includes means for coupling to an associated source of shielding gas and conduits through the body assembly for passing the shielding gas to the nozzle assembly in surrounding relationship with the tips. 
     
     
       9. The apparatus of  claim 1 , wherein the apparatus includes a housing for the body assembly having a pistol-grip handle. 
     
     
       10. The apparatus of  claim 1 , and further comprising a housing for the body assembly and means for removably mounting the housing on an associated support in a fixed position. 
     
     
       11. In an arc welding apparatus for delivering to a workpiece first and second wire electrodes respectively adapted to be coupled to first and second sources of electric power, and including a nozzle assembly for channeling other utilities to a working end of the apparatus, the improvement comprising: 
       first and second bodies coupled to the nozzle assembly and adapted to be connected respectively to the first and second sources of electric power and respectively receiving the first and second electrodes for connecting the electrodes respectively to the first and second sources of electric power and for supporting the electrodes through the nozzle assembly,  
       means for electrically insulating the first and second bodies from each other, and  
       two tips respectively removably mechanically and electrically connected to the bodies for respectively slidably receiving and electrically contacting the first and second electrodes and guiding them to the associated workpiece.  
     
     
       12. The apparatus of  claim 11 , and further comprising means for detachably coupling the nozzle assembly to the bodies. 
     
     
       13. The apparatus of  claim 12 , wherein the coupling means includes a docking body removably coupled to the bodies, and means for removably mounting the nozzle assembly on the docking body. 
     
     
       14. The apparatus of  claim 13  wherein the nozzle assembly includes cooling fluid recirculation conduits therein, the body assembly having cooling fluid passages therethrough communicating with the conduits, and means on the body assembly for coupling the passages to an associated supply of cooling fluid. 
     
     
       15. The apparatus of  claim 14 , wherein the docking body includes normally-closed valves respectively disposed in the passages, the nozzle assembly including actuators engageable with the valves when the nozzle assembly is mounted on the docking body for opening the valves. 
     
     
       16. The apparatus of  claim 14 , wherein the means for coupling to an associated cooling fluid supply includes means for connection to the first and second sources of electric power. 
     
     
       17. The apparatus of  claim 14 , and further comprising means for circulating cooling fluid through each of the first and second bodies. 
     
     
       18. The apparatus of  claim 11 , and further comprising means for threadedly coupling the two tips respectively to the first and second bodies. 
     
     
       19. The apparatus of  claim 11 , and further comprising means for coupling each of the first and second bodies to a supply of shielding gas, and passages in the first and second bodies for passing shielding gas to the nozzle assembly in surrounding relationship with the tips. 
     
     
       20. The apparatus of  claim 11 , and further comprising a housing enclosing the first and second bodies and adapted to be removably mounted on an associated fixed support. 
     
     
       21. An arc welding apparatus for delivering two wire electrodes to a workpiece comprising: 
       a body assembly adapted to be coupled to a source of electric power and directing the electrodes toward a working end of the apparatus,  
       a nozzle assembly removably coupled to the body assembly for channeling other utilities to the working end,  
       an adapter electrically and mechanically coupled to the body assembly for receiving the electrodes therefrom and maintaining the electrodes spaced from each other, and  
       a tip assembly removably mounted on the adapter in electrical connection therewith and including a single tip body defining two channels for respectively slidably receiving and electrically contacting the electrodes and guiding them to the associated workpiece, whereby  
       the tip assembly is removable from the apparatus without removing the nozzle assembly or the adapter.